Name Date Class

LESSON 1

Describing Weather

A. What is weather?

1. The atmospheric conditions, along with short-term changes, make up the

of a certain place at a certain time.

B. Weather Variables

1. Scientists who study and predict weather are .

2. Air is the measure of the average kinetic energy of

molecules in the air. Molecules in warm air move than

molecules in cooler air.

3. is the pressure that a column of air exerts on the air or

surface below it.

a. Air pressure decreases as altitude .

b. A(n) is an instrument used to measure air pressure.

4. is caused by air moving from an area of high pressure

to an area of low pressure.

a. In a south wind, the wind is coming from the .

b. The instrument used to measure wind speed is a(n) .

5. The amount of water vapor in the air is .

a. When air is , it holds the maximum amount of water

vapor possible at that .

b. is the amount of water vapor in the air compared to

the maximum amount of water vapor the air can hold at that temperature.

c. Relative humidity is reported as a(n) .

6. When air near the ground becomes saturated, the water vapor condenses into a

liquid and forms .

a. If the temperature is below 0°C, ice crystals, referred to as

, form.

b. The temperature at which air becomes fully saturated because the

temperature decreases while the amount of moisture stays constant is

the .

10 Weather

Lesson Outline

Name Date Class

Lesson Outline continued

7. As warm air rises in the atmosphere, it .

a. When the air cools enough that the is reached, small

droplets of water form.

b. are water droplets or ice crystals suspended in the

atmosphere.

c. is a cloud that forms near Earth’s surface.

d. clouds are flat, white, and layered.

e. clouds are fluffy and are present at 2,000 to 6,000 m

altitude.

f. clouds are wispy and are present above 6,000 m

altitude.

8. is water, in liquid or solid form, that falls from the

atmosphere.

a. Precipitation that falls as liquid water is .

b. Precipitation that is solid crystals of ice is .

c. Precipitation that starts as snow and then melts and freezes again is

called .

d. is precipitation formed when ice pellets rise and fall

within a cloud, adding new layers of ice during each cycle.

9. The is the series of natural processes in which water

continually moves among oceans, land, and the atmosphere.

a. Water enters the atmosphere as water vapor when liquid water on Earth’s

surface .

b. As water vapor cools, it , forming liquid water.

c. Clouds produce , which is when liquid or frozen

water falls to Earth’s surface.

Weather 11

Name Date Class

LESSON 1

Describing Weather

Rain Snow Sleet Hail

Directions: Use the diagram to answer each question.

Question Rain Snow Sleet Hail

What form is the water in when it is in the clouds— liquid or solid?

What is the air temperature near the clouds—warm or cold?

What is the air temperature near Earth’s surface—warm or cold?

What is the form of precipitation that falls— liquid or solid?

How are rain, snow, sleet, and hail part of the water cycle?

What role does temperature

play in the type of precipitation that develops?

Weather 13

Content Practice A

Name Date Class

LESSON 1

Describing Weather

Key Concept What is weather?

Directions: Put a check mark in the correct column to answer the question about weather. Then explain each answer.

Does this fit the definition of weather? Yes No Why or why not?

1. It has been raining where you live for the past hour.

2. The average temperature in the summer is 42°C.

3. The temperature decreases 5°C in one hour and then decreases another 3°C in the next hour.

4. The day began sunny, but now there are plenty of clouds.

5. The region gets an average of 2.5 cm of rain each year.

6. You want to go on a bike ride, but you decide to go outside to check for dark clouds.

7. Heavy rainstorms are predicted for the next two hours, after which the sky should clear.

8. Ice formations are present across the region throughout the year.

9. Plants that require high amounts of moisture year-round grow in the area.

10. The clouds seem to be moving quickly, and the wind has started to blow harder.

11. The day began sunny, but now you wish you had an umbrella.

16 Weather

Key Concept Builder